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Abstract:

The present invention discloses a dual-vision driving safety warning
device and a method thereof. The device of the present invention
comprises an image capture unit, an image processing unit, a vehicle
status sensing unit, a warning judgment logic, and at least one warning
unit. The image capture unit includes at least two image capture devices
installed in a user's vehicle and capturing the images of the front
traffic environment. The image processing unit processes the images and
uses the vehicle status signals detected by the vehicle status sensing
unit to calculate the distance between the user's vehicle and a front
vehicle in the image. The warning judgment logic sends out a control
signal when the user's vehicle deviates from a driving lane or approaches
a front vehicle too much. The warning unit receives the control signal
and sends out a warning signal, such as a sound or a flash, to remind the
driver.

Claims:

1. A dual-vision driving safety warning device comprising an image
capture unit including at least two image capture devices installed in a
user's vehicle and capturing images of a front traffic environment,
wherein said images at least contain images of complete lane marks; a
vehicle status sensing unit sensing at least one status signal of said
user's vehicle, including a signal of speed, braking, or a direction
light; an image processing unit including a lane mark detection
algorithm, a detection angle algorithm, a front vehicle detection
algorithm, a distance estimation algorithm and a distance calibration
algorithm, and used to process said images and calculate a distance
between said user's vehicle and a front vehicle; a warning judgement
logic integrating said vehicle status signal and calculation results of
said image processing unit to perform an adaptive cruise control function
and sending out a control signal when said user's vehicle deviates from a
driving lane or approaches said front vehicle too much; and at least a
warning unit connected said the image processing unit and said vehicle
status sensing unit, and controlled by said control signal to send out a
warning signal.

2. The dual-vision driving safety warning device according to claim 1,
wherein said distance estimation algorithm roughly estimates distances of
a front vehicle in images captured by said image capture devices, and
wherein said distance calibration algorithm intercompares and calibrates
said distances to obtain a correct distance to said front vehicle.

3. The dual-vision driving safety warning device according to claim 1,
wherein when said image capture devices respectively have different
elevation angles, said image capture devices respectively capture a
near-field image and a far-field image, and wherein said detection angle
algorithm uses said elevation angles with respect to a front vehicle in
said near-field image and said far-field image to calculate a distance to
said front vehicle.

4. A dual-vision driving safety warning method comprising steps: using an
image capture unit installed in a user's vehicle to capture at least one
image of a front traffic environment, wherein said image at least
contains images of complete lane marks; using an image processing unit to
process said image, wherein said processing unit makes use of processing
results and at least one vehicle status signal detected by a vehicle
status sensing unit to calculate a distance between said user's vehicle
and a front vehicle in said image; and using a warning judgement logic to
output a control signal to enable at least a warning unit to send out a
warning signal when said user's vehicle deviates from a driving lane or
approaches said front vehicle too much.

6. The dual-vision driving safety warning method according to claim 4,
wherein said image processing unit uses a lane mark detection algorithm,
a detection angle algorithm, a front vehicle detection algorithm, a
distance estimation algorithm and a distance calibration algorithm to
calculate a distance between said user's vehicle and a lane mark and a
distance between said user's vehicle and a front vehicle.

7. The dual-vision driving safety warning method according to claim 6,
wherein said front vehicle detection algorithm uses a Sobel edge
detection method to detect horizontal edges and vertical edges of a front
object and determine whether a width and a height of said front object
match dimensions of a normal vehicle, and wherein if said width and said
height of said front object match said dimensions of said normal vehicle,
said distance estimation algorithm is used to estimate a distance to said
front vehicle.

8. The dual-vision driving safety warning method according to claim 6,
wherein said distance estimation algorithm roughly estimates distances of
a front vehicle in images captured by said image capture devices, and
wherein said distance calibration algorithm intercompares and calibrates
said distances to obtain a correct distance to said front vehicle.

9. The dual-vision driving safety warning method according to claim 6,
wherein when said image capture devices respectively have different
elevation angles, said image capture devices respectively capture a
near-field image and a far-field image, and wherein said detection angle
algorithm uses said elevation angles with respect to a front vehicle in
said near-field image and said far-field image to calculate a distance to
said front vehicle.

10. The dual-vision driving safety warning method according to claim 6,
wherein distances are respectively worked out from said near-field image
and said far-field image, and wherein said distances are intercompared
and calibrated to obtain a correct distance.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a driving safety warning
technology, particularly to a dual-vision driving safety warning device
and a method thereof.

[0003] 2. Description of the Related Art

[0004] The conventional driving safety warning systems normally use a
laser or radar to detect the distance between the user's vehicle and the
front obstacle/vehicle to prevent from the collision between the user's
vehicle and the front vehicle. However, the conventional systems are
expensive and incapable of perceiving driving lane deviation or
recognizing traffic signs. Therefore, the visibility of the conventional
driving safety warning systems is very low in the market.

[0005] Thus, the visual-type driving safety warning system gradually earns
attention. In comparison with the laser or radar driving safety warning
system, the visual driving safety system can recognize the traffic
environment, such as lane marks, traffic signs and obstacles and has
advantages of low cost and high integration capability. However, the
current visual driving safety warning system is limited by the adopted
lens and unable to detect the near field and the far field at the same
time. Thus, the current visual driving safety warning systems is normally
designed to only detect the near field. So far, the visual driving safety
warning system able to detect the far field has not appeared yet. In
fact, the greater the detection range and the higher the environment
recognizability, the better the performance of the visual driving safety
warning system. Obviously, the conventional technology cannot meet the
requirement.

[0006] Accordingly, the present invention proposes a dual-vision driving
safety warning device and a method thereof to overcome the abovementioned
problems. The principles and embodiments of the present invention will be
described in detail below.

SUMMARY OF THE INVENTION

[0007] The primary objective of the present invention is to provide a
dual-vision driving safety warning device and a method thereof, wherein
at least two image capture devices are installed in the use's vehicle to
respectively capture the images of the near filed and far field, and
wherein the system estimates the distance between the user's vehicle and
the front vehicle.

[0008] Another objective of the present invention is to provide a
dual-vision driving safety warning method, wherein makes use of the tilt
angles (elevation angles) of the image capture devices to intercompare
and calibrate the roughly-estimated distance, and which examines whether
the user's vehicle deviates from the driving lane or two vehicles are too
close and provides corresponding warnings.

[0009] A further objective of the present invention is to provide a
dual-vision driving safety warning method, wherein when the two image
capture devices have an identical elevation angle, the detection of the
front vehicle in the far field and the distance to the far-field front
vehicle can be obtained from the detection range and the elevation angle
of the near-field image capture device, whereby the present invention is
exempted from the difficulty of detecting a far-field object in a
vibrating vehicle.

[0010] To achieve the abovementioned objectives, the present invention
proposes a dual-vision driving safety warning device, which comprises at
least two image capture devices installed in a user's vehicle and
capturing images of the front traffic environment, including images of
complete lane marks; a vehicle status sensing unit sensing at least one
vehicle status signal, including signals of speed, braking and direction
lights; an image processing unit processing the images and calculating
the distance between the user's vehicle and a front vehicle in the image;
a warning judgement logic integrating the vehicle status signals and the
calculation results of the image processing unit to perform an adaptive
cruise control function and sending out a control signal when the user's
vehicle deviates from the driving lane or two vehicles are too close; at
least one warning unit connected with the image processing unit and the
vehicle status sensing unit and controlled by the control signal to send
out a warning signal.

[0011] The present invention also proposes a dual-vision driving safety
warning method, which comprises steps: using an image capture unit
installed in a user's vehicle to capture images of the front traffic
environment, including images of complete lane marks; using an image
processing unit to process the images, wherein the image processing unit
further makes use of processing results and the vehicle status signal
detected by a vehicle status sensing unit to calculate the distance
between the user's vehicle and a front vehicle in the image; and using a
warning judgement logic to output a control signal to enable a warning
unit to send out a warning signal when the user's vehicle deviates from
the driving lane or two vehicles are too close.

[0012] Below, the embodiments will be described in detail to make easily
understood the objectives, technical contents, characteristics and
accomplishments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is a block diagram schematically architecture of a
dual-vision driving safety warning device according to one embodiment of
the present invention;

[0014] FIG. 2 is a flowchart of a dual-vision driving safety warning
method according to one embodiment of the present invention;

[0015]FIG. 3A is a diagram schematically showing the detection of a
vanishing point, and FIG. 3B is a diagram schematically showing the
method of using the elevation angles to estimate the distance to the
front vehicle;

[0016]FIG. 4 is a diagram schematically showing an overlapped area of a
near-field image and a far-field image;

[0017]FIG. 5A and FIG. 5B are flowcharts of the distance calibration
processes;

[0018]FIG. 6A and FIG. 6B are respectively flowcharts of the
small-vehicle warning process and the large-vehicle warning process; and

[0019] FIG. 7 is a flowchart of a dual-vision driving safety warning
method in an embodiment wherein the two image capture devices
respectively have different angles.

DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention proposes a dual-vision driving safety warning
device and a method thereof, which can obtain the information of the
traffic environment, provides an intelligent vehicle-following function
for the driver and prevents the driver from an inattentive driving
behavior, such as deviating from the driving lane or approaching the
front vehicle too much.

[0021] Refer to FIG. 1 a block diagram schematically architecture of a
dual-vision driving safety warning device according to one embodiment of
the present invention. The device of the present invention comprises at
least one image capture unit 10, an image processing unit 12, a vehicle
status sensing unit 14, a warning judgement logic 16 and a warning unit
18. The image capture unit 10 includes at least two image capture devices
installed in a user's vehicle and capturing the images of the front
traffic environment. The two image capture devices respectively capture
the near-field images and the far-field images. The vehicle status
sensing unit 14 sensing the status signals of the user's vehicle, such as
the signals of speed, braking, and direction lights. The image processing
unit 12 includes a lane mark detection algorithm, a detection angle
algorithm, a front vehicle detection algorithm, a distance estimation
algorithm, and a distance calibration algorithm. The image processing
unit 12 utilizes the algorithms and the vehicle status signals detected
by the vehicle status sensing unit 14 to calculate the distance between
the user's vehicle and a front vehicle in the image. The warning
judgement logic 16 integrates the vehicle status signals and the
calculation results of the image processing unit 12 to perform an
adaptive cruise control function and sends out a control signal when the
user's vehicle deviates from the driving lane or approaches the front
vehicle too much. The warning unit 18 is connected with the image
processing unit 12 and the vehicle status sensing unit 14 and controlled
by the control signal of the vehicle status sensing unit 14 to send out a
warning signal, such a buzzer sound or a LED light.

[0022] Refer to FIG. 2 a flowchart of a dual-vision driving safety warning
method according to one embodiment of the present invention. In Step S10,
the device of the present invention is started. In Step S12, the vehicle
status sensing unit detects whether the speed of the user's vehicle
exceeds a preset value. In one embodiment, the preset value is 60 km/h.
If the speed does not exceed the preset value, the process returns to
Step S10. If the speed exceeds the preset value, the process proceeds to
the next step. The two image capture devices respectively have different
elevation angles to capture near-field images and far-field images for
distance calculation. In Step S1-Step S20, one image capture device
captures near-field images, and the lane mark detection algorithm detects
the positions of the lane marks to determine the detection range and
whether the user's vehicle deviates from the lane marks. If the extension
line of the user's vehicle intersects the lane mark and the direction
light on the same side is turned on, the process proceeds to Step S22,
and the warning unit sends out a warning signal to warn the user that his
vehicle is deviating from the driving lane. In Step S14'-Step S20',
another image capture device captures far-field images, and the lane mark
detection algorithm detects the positions of the lane marks to determine
the detection range and whether the user's vehicle deviates from the lane
marks. If the user's vehicle is deviating from the driving lane, the
process proceeds to Step S22, and the warning unit sends out a warning
signal to warn the user that his vehicle is deviating from the driving
lane.

[0023] If the system determines that the user's vehicle does not deviate
from the driving lane in Step S20 and Step S20', the two image capture
devices respectively detect the vanishing points of the near field and
the far field in Step S24 and Step 24'. Refer to FIG. 3A, wherein the
image has a vanishing point, an image center, and a front object (a front
vehicle), and wherein d1 denotes the distance between the vanishing point
and the image center, and wherein d2 denotes the distance between the
image center and the front object. In Step S26 and Step S26', the
detection angle algorithm calculates the elevation angles of the two
image capture devices. In Step S28 and Step S28', the front vehicle
detection algorithm determines whether the front object is a vehicle.
Firstly, the lane marks are detected. Next, a Sobel edge detection method
is used to detect the horizontal edges and vertical edges of the front
object and determine whether the width and height of the front object
match the dimensions of a normal vehicle. If they match, the distance
estimation algorithm calculates the distance between the user's vehicle
and the front vehicle in Step S30 and Step S30'. Refer to FIG. 3B for the
distance estimation method. In FIG. 3B, two image capture devices 22 are
installed in a user's vehicle 20, but the two image capture devices 20
coincides with each other in the side view. The image capture devices 22
are at an altitude of H; the distance between the user's vehicle 20 and a
front vehicle 24 is D; the two image capture devices 22 have an identical
focal length f; the two image capture devices 22 respectively have
elevation angles of α1 and α2. The distance D can be roughly
estimated from the following equation:

[0024] After the distance D to the front vehicle has been estimated, the
near-field image capture device and the far-field image capture device
respectively determine whether there is any vehicle existing in the
preset range in Step S32 and Step S32'. In one embodiment, the preset
range is from 30 to 50 m. Refer to FIG. 4. The near-field detection range
and the far-field detection overlap in the range from 30 to 50 m. If
there is no vehicle in the overlapped area, the system examines whether
the distance to the front vehicle is too small according to the speed of
the user's vehicle in Step S36. If the distance to the front vehicle is
indeed too small, the system sends out a collision warning message in
Step S38. If there is a vehicle in the overlapped area, the distance
calibration algorithm calibrates the roughly-estimated distance in Step
S34.

[0025] Refer to FIG. 5A and FIG. 5B for the details of the distance
calibration process of Step S34 in FIG. 2. In Step S50 and Step S52, the
system examines whether the object from a far position to a near position
has the characteristic of a vehicle, wherein the system uses the Sobel
edge detection method to examine whether the horizontal edges and the
vertical edges of the object match the dimensions of a normal vehicle. If
the horizontal edges and the vertical edges of the object match the
dimensions of a normal vehicle in Step S52, the system uses the Sobel
edge detection method to examine whether the object from a near position
to a far position has the characteristic of a vehicle in Step S54 and
Step S56. If the horizontal edges and the vertical edges of the object
match the dimensions of a normal vehicle in Step S56, the system compares
the object with a vehicle template in Step S58. If the horizontal edges
and the vertical edges of the object do not match the dimensions of a
normal vehicle in Step S56, a far-field detection position is adopted in
Step S60. If the horizontal edges and the vertical edges of the object do
not match the dimensions of a normal vehicle in Step S52, the system uses
the Sobel edge detection method to examine whether the object from a near
position to a far position has the characteristic of a vehicle in Step
S62 and Step S64. If the object matches the characteristic of a normal
vehicle in Step S64, a near-field detection position is adopted in Step
S66. If the object does not match the characteristic of a normal vehicle
in Step S64, it means that the detection fails, and the detection will be
undertaken again in the next image (Step S68). FIG. 5B shows the process
of vehicle template comparison. In Step S70, the system takes the imager
block of the front vehicle in the far-field image. In Step S72, the
system zooms (expands) the image block by a ratio of the vehicle width in
the near-field image/the vehicle width in the far-field image. In Step
S74, the image blocks subtract for comparison. In Step S76, the system
determines whether the difference of the image blocks is smaller than the
preset threshold. If the difference is not smaller than the preset
threshold, the detection is determined to be a failure in Step S78, and
the detection will be undertaken again in the next image. If the
difference is smaller than the preset threshold, the system outputs the
distance in Step S79.

[0026] The system uses the distance output in Step S79 and the speed of
the user's vehicle to determine whether the user's vehicle approaches the
front vehicle too much in Step S36. If the user's vehicle indeed
approaches the front vehicle too much, a front-collision warning is sent
out in Step S38.

[0027] In Step S32' of FIG. 2, the system examines whether there is any
vehicle existing in the far-field image within the range of from 30 to 50
m. If there is a vehicle in the range, the abovementioned calibration is
undertaken in Step S34. If there is no vehicle in the range, the system
sends out a small-vehicle warning in Step S40 or a large-vehicle warning
in Step S42. Refer to FIG. 6A for the process of the small-vehicle
warning. In Step S400, the system acquires the distance to the front
vehicle in the far-field image. In Step S402, the system uses the
distance to the front vehicle and the vehicle status signals (such as the
speed signal) output by the vehicle status sensing unit to determine
whether the distance is greater than the preset safe distance. If the
distance is not greater than the safe distance, the system examines
whether the value of the distance is smaller than half the value of the
speed (the preset value in the embodiment) in Step S404. If the value of
the distance is smaller than half the value of the speed, the system
sends out a front-collision warning to remind the user not to approach
the front vehicle too much in Step S406. If the distance is greater than
the safe distance in Step S402, the system examines whether the value of
the speed multiplied by a preset time is greater than the distance in
Step S408. If the value of the speed multiplied by the preset time is
greater than the distance, the system automatically slows down the user's
vehicle in Step S410. If the value of the speed multiplied by the preset
time is not greater than the distance, the system automatically speeds up
the user's vehicle in Step S412. What is undertaken in Step S410 and Step
S412 is the so-called adaptive cruise control function, wherein the
dual-vision driving safety warning device of the present invention
controls the accelerator to maintain the safe distance between the user's
vehicle and the front vehicle according to the speed of the user's
vehicle. Once the user pushes down the brake, the adaptive cruise control
function is shut down. Refer to FIG. 6B for the process of the
large-vehicle warning. In Step S420, the system acquires the distance to
the front vehicle in the far-field image. In Step S422, the system
examines whether the distance is smaller than the value of the speed
subtracted by 20 (the preset value in the embodiment). If the distance is
smaller than the value of the speed subtracted by 20, the system sends
out a front-collision warning (Step S424). If the distance is not smaller
than the value of the speed subtracted by 20, the process returns to Step
S420.

[0028] One characteristic of the present invention is that the device of
the present invention has two image capture devices respectively having
different elevation angles for capturing the near-field images and the
far-field images. When the two image capture devices have an identical
elevation angle, Step S16'-Step S28' can be omitted, as shown in FIG. 7.
In such a case, the far-field vehicle detection of Step S28' is
undertaken in the detection range determined by the near-field image; the
distance to the front vehicle in the far-field image is calculated from
the elevation angle of the near-field image capture device.

[0029] In conclusion, the present invention proposes a dual-vision driving
safety warning device and a method thereof. The device of the present
invention comprises at least two image capture devices, which
respectively capture the near-field and far-field images at the same time
to detect the lane marks and estimate the distance to the front vehicle.
The distances respectively detected by the near-field and far-field image
capture devices are intercompared to calibrate the estimated distance.
Further, the device determines whether to send out a warning, considering
the distance to the front vehicle and the vehicle status signals of the
user's vehicle. Thereby, the present invention can perform a driving lane
deviation warning, a front-collision warning and an adaptive cruise
control function, exempt from the interference by the vibration of the
vehicle.

[0030] The embodiments described above are only to exemplify the present
invention but not to limit the scope of the present invention. Any
equivalent modification or variation according to the spirit of the
present invention is to be also included within the scope of the present
invention.

Patent applications by Chia-Tseng Chen, Changhua County TW

Patent applications by Yi-Feng Su, Changhua County TW

Patent applications by Yu-Sung Chen, Changhua County TW

Patent applications by AUTOMOTIVE RESEARCH & TEST CENTER

Patent applications in class Of relative distance from an obstacle

Patent applications in all subclasses Of relative distance from an obstacle